In the state of the art, it is known to make a time base device for a timepiece movement with an oscillator connected to a quartz resonator. This time base device also includes a frequency divider for dividing the oscillator frequency, and a control circuit for an electric motor connected to the frequency divider. The electric motor is controlled by the control circuit for driving, in particular, the hands of a time display, for example on a watch dial.
Each element of the time base device is generally secured to at least one printed circuit board, on which electrical connections are made between the various electronic elements of the time base device. The printed circuit board, including the time base device, may also be connected to the watch movement. These different elements are also powered by a voltage source, such as a battery or accumulator, which may be mounted in a housing provided for this purpose, which is connected to the printed circuit board. The assembly of all of these time base device electronic elements thus occupies a relatively large volume, which is a drawback for assembly or integration in a timepiece of small dimensions.
In order to reduce the volume of the electronic element assembly of the time base device, it is known to use a quartz resonator, in the form of a tuning fork associated with an oscillator, to form one part of the time base. The tuning fork quartz resonator and the integrated circuit including the oscillator may be grouped together within the same case.
Grouping together various electronic components in the same case is known, in particular from U.S. Pat. No. 3,784,725. In that document, an electronic assembly for a watch forms a single unit. Electronic components of the assembly are mounted and connected, generally individually, on a printed circuit board, which may create some problems and costs for mounting in a watchcase of small dimensions. However, this electronic assembly groups together all of the electronic components, and the dial, to facilitate mounting the assembly in a conventional watch movement, a plastic watchcase or a piece of jewellery.
Although the prior solutions can partly reduce the volume occupied particularly by some components of a time base, the available space remains, nonetheless, insufficient to make a timepiece of small dimensions. The need to mount several integrated circuits to perform several watch functions on one or more printed circuit boards means that a large amount of space is occupied in the watch. This requires increasing the volume of the watch excessively, which is undesirable.